| 摘要 |
<p>The invention relates to a method of preparation of thermodegradable polyurethane foams, characterized in that at least one bifunctional azo-compound having the general formula X-CH2-C(R1R2)-N=N-C(R1R2)-CH2-X, wherein X is -OH, -COOH or -COOMe and R1 and R2 are C1-C20 alkyl or C5-C20 cycloalkyl, is mixed with at least one polyisocyanate compound having the general formula R(NCO)n, wherein n represents an integer from 2 to 5, R is selected from the group comprising an aliphatic hydrocarbon containing 2-18 carbon atoms, cycloaliphatic hydrocarbon having 4-15 carbon atoms, arylalkyl having 8-15 carbon atoms and an aromatic hydrocarbon containing 6-15 carbon atoms, at the temperature of from 20 °C to 50 °C, thereby forming an azoisocyanate precursor, which is subsequently mixed with at least one polyol, wherein the isocyanate index [NCO]/[OH] x 100 is in the range of from 70 to 120, and with at least one blowing agent in the presence of at least one catalyst. The mixture is after mixing poured into a mould and reacts afterwards in open air approximately for 48 hours.</p> |
